Mercury Involvement in Neuronal Damage and in Neurodegenerative Diseases

Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis are characterized by a chronic and selective process of neuronal cell death. Although the causes of neurodegenerative diseases remain still unknown, it is now a well-established idea that more factors, such as genetic, endogenous, and environmental, are involved. Among environmental causes, the accumulation of mercury, a heavy metal considered a toxic agent, was largely studied as a probable factor involved in neurodegenerative disease course. Mercury exists in three main forms: elemental mercury, inorganic mercury, and organic mercury (methylmercury and ethylmercury). Sources of elemental mercury can be natural (volcanic emission) or anthropogenic (coal-fired electric utilities, waste combustion, hazardous-waste incinerators, and gold extraction). Moreover, mercury is still used as an antiseptic, as a medical preservative, and as a fungicide. Dental amalgam can emit mercury vapor. Mercury vapor, being highly volatile and lipid soluble, can cross the blood-brain barrier and the lipid cell membranes and can be accumulated into the cells in its inorganic forms. Also, methylmercury can pass through blood-brain and placental barriers, causing serious damage in the central nervous system. This review describes the toxic effects of mercury in cell cultures, in animal models, and in patients with neurodegenerative diseases. In vitro experiments showed that mercury exposure was principally involved in oxidative stress and apoptotic processes. Moreover, motor and cognitive impairment and neural loss have been confirmed in various studies performed in animal models. Finally, observational studies on patients with neurodegenerative diseases showed discordant data about a possible mercury involvement.

A forensic hypothesis for the mystery of al-Hasan's death in the 7th century: Mercury(I) chloride intoxication

The puzzle of a mysterious death in the Middle Ages has been hypothesized in terms of contemporary forensic legal and scientific methods. That al-Hasan ibn-'Ali died in 669 aged just 45 has been forensically analyzed based on written sources that dictate eyewitness accounts of historical events. The report of the contemporaneous poisoning of another individual who resided under the same household as al-Hasan's and experienced similar, yet non-lethal, symptoms has served as the beginning of the analysis. In light of ancient (medieval) documents and through using mineralogical, medical, and chemical facts, it has been hypothesized that mineral calomel (mercury(I) chloride, Hg2Cl2) from a certain region in the Byzantine Empire (present-day western Turkey) was the substance primarily responsible for the murder of al-Hasan.

Inorganic mercury intoxication: A case report

Mercury is a heavy metal with unique physico-chemical properties, and it is well distributed throughout the environment, being present in soil, water and air. This non-essential element is considered by the World Health Organization (WHO) as one of the ten most troublesome chemical to public health. Its toxicity spectrum depends on the chemical form in which it presents: elemental (metallic), organic or inorganic. The known intoxications are mainly occupational (mining, agriculture, incineration) or related to the use of dental amalgams or the consumption of contaminated fish and shellfish. Nowadays, acute exposures to toxic amounts of mercury are increasingly rare, especially those involving inorganic mercury compounds. The rate is even lower if we refer to intentional poisonings. Although there is a growing understanding of the toxicokinetics of mercury, there is still a lack of studies that support the emerging theories about its bioavailability in humans. In this manuscript we describe a rare case of an individual who committed suicide by ingesting mercuric oxide. The aim is to offer a medical contribution to the better understanding of the kinetics of this metal, making a discussion based on published literature and analyzing its distribution, metabolism, internal doses, target and reservoir organs. The whole case - clinical course of the victim and her fatal destiny, the ante- and post-mortem sample concentrations and the necropsy findings - illustrates a situation that meets specific features of acute poisoning by ingestion of inorganic mercury, thus constituting an important support towards a more realistic and a based on evidence understanding of mercury biodistribution in humans.

Health assessment of artisanal gold miners in Indonesia

Small scale miners use mercury to extract gold from ore in many countries. An environmental and health assessment was performed in Indonesia in two regions, Galangan in Central Kalimantan and Talawaan in Northern Sulawesi. The environmental assessment showed severe mercury contamination of the sediments, and increased mercury levels in local fish. For the health investigation 281 volunteers were recruited and examined by a standardized questionnaire, a neurological examination and neuro-psychological tests. A medical score was used consisting of significant factors of mercury intoxication. Mercury exposed workers showed typical symptoms of mercury intoxication, such as movement disorders (ataxia, tremor, dysdiadochokinesia, etc.). Blood, urine and hair samples were taken from any participant and analyzed for mercury. The mercury concentration in the biomonitors was high, partly extreme high in the working population, increased in the population living in the same habitat and low in the control group. By a standard protocol which includes a combination of threshold values of mercury in the biomonitors and a medical sum score the diagnosis of chronic mercury intoxication was made for highly burdened workers (amalgam smelters) in 55% in Sulawesi and in 62% in Kalimantan. Less exposed mineral processors and the general population in the mining areas were also intoxicated to a high percentage.

Health assessment of artisanal gold miners in Tanzania

In 2003 UNIDO (United Nations Industrial Development Organization) conducted an environmental and health assessment in a small-scale mining area in Tanzania. BGS (British Geological Survey) performed the environmental assessment. The Institute of Forensic Medicine - University of Munich performed the health assessment. The results of the medical, neurological and neuro-psychological examination of 180 participants from the affected area of Rwamagasa and 31 controls were analyzed. Urine, blood and hair samples were analyzed to detect the level of mercury body burden. Mercury concentrations in the bio-monitors urine, blood and hair were statistically significantly higher in the exposed population from Rwamagasa compared to the control group from Katoro. Only amalgam burners showed mercury levels above the toxicological threshold limits. A speciation of mercury in hair indicated that mainly elemental mercury vapor contributed to the high body burden of the artisanal miners. 104 amalgam-burners, the most exposed population group, were examined. 25 of these workers were found to be intoxicated. Small-scale mining is a serious health hazard for amalgam burners. Reduction of the exposure is essential to prevent further damage.

[Neuropsychologic traits in individuals with chronic exposure to mercury at work]

The article deals with diagnostic peculiarities of neuropsychologic traits in individuals with previous exposure to industrial neurotoxic chemicals. Pilot studies demonstrated brain disorders characteristic for toxic (mercurial) and vascular (discirculatory) encephalopathies, justified necessity of neuropsychologic approach in occupational therapeutic diagnosis. The authors presented results of suggested scheme of neuropsychologic prompt screening aimed to reveal higher psychic functional disorders in individuals with occupational neurointoxications.

Baboon syndrome induced by mercury - first case report in China

A case of mercury-induced baboon syndrome was reported. A 31-year-old woman presented with itching papules and vesicles in the right axilla, which extended to the left axilla, arms, fossa poplitea, buttocks, and groin. A mercury thermometer was broken 2 days before exanthema. Patch testing to ammoniated mercury, mercury, mercuric chloride, and mercurochrome were positive. Blood and urine mercury level was marginally normal, yet showed a descending trend over time.

The toxicology of mercury and its chemical compounds

This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."

[Analysis of adverse effects of cinnabar]

This article made a brief analysis of clinical adverse effects of cinnabar. Except for allergic reaction, almost all the adverse events of cinnabar were caused by unreasonable application. The majority of the poisoning cases were associated with excessive and/or long-term dosage, and improper preparation methods, such as decocting, heating or fumigating. Children showed to be prone to poisoning. The poisoning caused by unreasonable use of cinnabar should be considered to be drug alert, but not advert effect. And the toxicity of cinnabar could be avoided by normalizing the preparation method, controlling the dosage and duration.

Is shellfish consumption safe?

Louisiana provides nearly 40% of domestic seafood production. America's commercial fisheries, especially coastal shellfish fisheries, now face crippling economic and environmental pressures from seafood imports, over-fishing, urban and agricultural wastewater runoff, harmful algal blooms, and coastal wetlands loss. As a result of these ecosystem stresses, seafood-borne disease now causes 37% of all foodborne illness in the United States. Louisiana and other coastal-state physicians can effectively curtail the rising threat of local shellfish-borne disease outbreaks by supporting responsible coastal restoration and regulation of commercial shell-fishing, especially oyster fishing, and by recommending careful selection and preparation of all shellfish and crustaceans.

A fatal case of mercuric cyanide poisoning

A 57-year-old pharmacist was found dead 11 days after his disappearance. At the autopsy, samples of blood, urine, gastric content were obtained. Presence of ethanol, cyanide and mercury were detected in some samples. Cyanide and mercury were identified and quantified using high-performance liquid chromatography with diode array detector (HPLC) in fluorescence mode and ICP with mass selective detector (ICP-MS) respectively. Whole blood concentrations of ethanol was 1.72 g/L. Cyanide and mercury concentrations in whole blood were respectively 0.16 and 3.8 mg/L. Concentrations of cyanide (27 mg/L) and mercury (150 mg/L) in gastric contents prove a massive oral ingestion of mercuric cyanide or mercuric oxycyanide occurred. In this case report, the death was attributed to the combined toxicity of cyanide and mercury.

Mercury vapor inhalation from Chinese red (Cinnabar)

INTRODUCTION

Acute inhalation of mercury fumes or vapors is a rare but frequently fatal cause of acute lung injury. This report describes a rare cause of mercury inhalation from Chinese red.

CASE REPORT

An 87-year-old male inhaled the vapors from heating Chinese red (Cinnabar, mercury sulphide) intended to treat his foot ulceration. He subsequently developed acute lung injury (progressive dyspnea and acute respiratory failure) that was treated with mechanical ventilation. DMPS (2,3-Dimercapto-1-propanesulfonic acid) and penicillamine were used as chelating agents, and methylprednisolone pulse therapy was used to treat his pulmonary disease. Despite being extubated once, the patient eventually died from profound hypoxemia.

CONCLUSION

A rare case of mercury intoxication was due to inappropriate use of an alternative medicine, Chinese red. This case serves as a reminder of the toxicity of the noxious gas from this substance and the importance of being familiar with alternative medicines.

Case report: severe mercuric sulphate poisoning treated with 2,3-dimercaptopropane-1-sulphonate and haemodiafiltration

INTRODUCTION

Inorganic mercury poisoning is uncommon, but when it occurs it can result in severe, life-threatening features and acute renal failure. Previous reports on the use of extracorporeal procedures such as haemodialysis and haemoperfusion have shown no significant removal of mercury. We report here the successful use of the chelating agent 2,3-dimercaptopropane-1-sulphonate (DMPS), together with continuous veno-venous haemodiafiltration (CVVHDF), in a patient with severe inorganic mercury poisoning.

CASE REPORT

A 40-year-old man presented with haematemesis after ingestion of 1 g mercuric sulphate and rapidly deteriorated in the emergency department, requiring intubation and ventilation. His initial blood mercury was 15 580 microg/l. At 4.5 hours after ingestion he was started on DMPS. He rapidly developed acute renal failure and so he was started on CVVHDF for renal support and in an attempt to improve mercury clearance; CVVHDF was continued for 14 days.

METHODS

Regular ultradialysate and pre- and post-filtrate blood samples were taken and in addition all ultradialysate generated was collected to determine its mercury content.

RESULTS

The total amount of mercury in the ultrafiltrate was 127 mg (12.7% of the ingested dose). The sieving coefficient ranged from 0.13 at 30-hours to 0.02 at 210-hours after ingestion. He developed no neurological features and was discharged from hospital on day 50. Five months after discharge from hospital he remained asymptomatic, with normal creatinine clearance.

DISCUSSION

We describe a patient with severe inorganic mercury poisoning in whom full recovery occurred with the early use of the chelating agent DMPS and CVVHDF. There was removal of a significant amount of mercury by CVVHDF.

CONCLUSION

We feel that CVVHDF should be considered in patients with inorganic mercury poisoning, particularly those who develop acute renal failure, together with meticulous supportive care and adequate doses of chelation therapy with DMPS.

Technical report: mercury in the environment: implications for pediatricians

Mercury is a ubiquitous environmental toxin that causes a wide range of adverse health effects in humans. Three forms of mercury (elemental, inorganic, and organic) exist, and each has its own profile of toxicity. Exposure to mercury typically occurs by inhalation or ingestion. Readily absorbed after its inhalation, mercury can be an indoor air pollutant, for example, after spills of elemental mercury in the home; however, industry emissions with resulting ambient air pollution remain the most important source of inhaled mercury. Because fresh-water and ocean fish may contain large amounts of mercury, children and pregnant women can have significant exposure if they consume excessive amounts of fish. The developing fetus and young children are thought to be disproportionately affected by mercury exposure, because many aspects of development, particularly brain maturation, can be disturbed by the presence of mercury. Minimizing mercury exposure is, therefore, essential to optimal child health. This review provides pediatricians with current information on mercury, including environmental sources, toxicity, and treatment and prevention of mercury exposure.

Fish consumption, fish lore, and mercury pollution--risk communication for the Madeira River people

Fish is an important food resource in Amazonian aquatic ecosystems. There is a strong cultural background regarding fish consumption (fish lore) among indigenous people in the Amazon. Mercury (Hg) ingestion through fish consumption has been a major route of Hg exposure among the riverside people along the Upper Madeira River. In this paper a diet questionnaire was used to identify patterns of fish consumption. The amount of fish consumed during the dry season and Hg levels in fish were combined to estimate Hg ingestion. Using as guidance hair Hg levels below 5 and 10 ppm as acceptable to protect the fetus and adult, respectively, along with an average daily fish consumption of 243 g per capita, we estimated the maximum acceptable number of fish meals per week for different fish species. Based on this analysis, it is suggested that there is a need to address risk communication for this exposed population in the context of health in terms of a fish advisory. For the fish advisory it is necessary to recommend to fish consumers, fishermen, and fish sellers an acceptable number of fish meals to be consumed according to species.

Benchmark concentrations for methylmercury obtained from the Seychelles Child Development Study

Methylmercury is a neurotoxin at high exposures, and the developing fetus is particularly susceptible. Because exposure to methylmercury is primarily through fish, concern has been expressed that the consumption of fish by pregnant women could adversely affect their fetuses. The reference dose for methylmercury established by the U.S. Environmental Protection Agency was based on a benchmark analysis of data from a poisoning episode in Iraq in which mothers consumed seed grain treated with methylmercury during pregnancy. However, exposures in this study were short term and at much higher levels than those that result from fish consumption. In contrast, the Agency for Toxic Substances and Disease Registry (ATSDR) based its proposed minimal risk level on a no-observed-adverse-effect level (NOAEL) derived from neurologic testing of children in the Seychelles Islands, where fish is an important dietary staple. Because no adverse effects from mercury were seen in the Seychelles study, the ATSDR considered the mean exposure in the study to be a NOAEL. However, a mean exposure may not be a good indicator of a no-effect exposure level. To provide an alternative basis for deriving an appropriate human exposure level from the Seychelles study, we conducted a benchmark analysis on these data. Our analysis included responses from batteries of neurologic tests applied to children at 6, 19, 29, and 66 months of age. We also analyzed developmental milestones (age first walked and first talked). We explored a number of dose-response models, sets of covariates to include in the models, and definitions of background response. Our analysis also involved modeling responses expressed as both continuous and quantal data. The most reliable analyses were considered to be represented by 144 calculated lower statistical bounds on the benchmark dose (BMDLs; the lower statistical bound on maternal mercury hair level corresponding to an increase of 0.1 in the probability of an adverse response) derived from the modeling of continuous responses. The average value of the BMDL in these 144 analyses was 25 ppm mercury in maternal hair, with a range of 19 to 30 ppm.

Toxicity of mercury

A ruling by the European Union heralds the demise of those useful clinical instruments, the mercury thermometer and the mercury sphygmomanometer. The new laws have been passed because of worries about mercury poisoning. Yet you can drink metallic mercury and come to no harm. What does it all mean? There are three forms of mercury from a toxicological point of view: inorganic mercury salts; organic mercury compounds; and metallic mercury. Inorganic mercury salts are water soluble, irritate the gut, and cause severe kidney damage. Organic mercury compounds, which are fat soluble, can cross the blood brain barrier and cause neurological damage. Mercury metal poses two dangers. It can be vaporised: the vapour pressure at room temperature is about 100 times the safe amount, so poisoning can occur if mercury metal is spilled into crevices or cracks in the floorboards. Dentists are occasionally poisoned this way. Mercury easily crosses into the brain, and causes tremor, depression, and behavioural disturbances. A second danger from metallic mercury is that it is biotransformed into organic mercury, by bacteria at the bottom of lakes. This can be passed along the food chain and eventually to man. It was this process that led to the Japanese tragedy at Minimata Bay in the late 1950s when over 800 people were poisoned. It is the need to reduce mercury contamination of the environment which should encourage us to cut the usage of metallic mercury. However, much more metallic mercury is spilled as waste by the chemical industry than is dropped on the floor in the clinic.

Urinary mercury in twelve cases of cutaneous mercurous chloride (calomel) exposure: effect of sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy

OBJECTIVE

To evaluate clinical symptoms and urinary mercury before and after chelation therapy in subjects with chronic cutaneous mercurous chloride (HgCl; calomel) exposure.

SUBJECTS

Twelve women from 19-45 years who had used a facial cream which contained HgCl (5.9%) for 2 to 10 years.

DESIGN

Twenty-four hour urine samples were collected for basal urine mercury. All the subjects received a 5-day cycle of oral sodium 2,3 dimercaptopropane-l-sulfonate (Dimaval capsules 100 mg) 200 mg/d on an outpatient basis. The urine mercury excretion was monitored 24 hours after the first dose and 72 hours after the last dose in eight subjects.

RESULT

Exanthem and tremor were detected in two of 12 subjects. The range of urine mercury was 180 to 1876 micrograms/g creatinine. A significant increase in the urinary mercury excretion was observed in the first 24 hours after beginning sodium 2,3-dimercaptopropane-1-sulfonate.

CONCLUSION

Chronic topical application of 5.9% HgCl cream was associated with clinical mercurialism in two subjects and with high urinary mercury level in all the cases. Sodium 2,3-dimercaptopropane-1-sulfonate was effective in increasing urine mercury.

Mercury poisoning with tooth loss: an 1813 case report

During the War of 1812, the medical surgeon and his "mate" were responsible for the soldiers' dental care; there were no dentists employed by the United States Army. Official reports of dental treatment are, therefore, rare.

[[The Swedish lex Maria--then and now. Injuries in health care in a historic perspective]

The Swedish system concerning injuries in the health care sector has its origin in an incident 1936 at the Maria hospital in Stockholm. Four patients died following injection of mercury oxycyanide instead of a local anaesthetic. The first law in 1937 focused on disciplinary actions with prescribed duties to report patient injuries both to the National Board of Health and Welfare and the local police. The regulations, often called lex Maria, have changed during the past 60 years. It is now stressed, beside the punitive aspects, that also incidents not causing injuries should be reported, that organisational factors should be considered in the evaluations of incidents and that a main aspect of the system is prevention.

Human exposure to mercury: a critical assessment of the evidence of adverse health effects

The ubiquitous nature of mercury in the environment, its global atmospheric cycling, and its toxicity to humans at levels that are uncomfortably close to exposures experienced by a proportion of the population are some of the current concerns associated with this pollutant. The purpose of this review is to critically evaluate the scientific quality of published reports involving human exposures to mercury and associated health outcomes as an aid in the risk evaluation of this chemical. A comprehensive review of the scientific literature involving human exposures to mercury was performed and each publication evaluated using a defined set of criteria that are considered standards in epidemiologic and toxicologic research. Severe, sometimes fatal, effects of mercury exposure at high levels were primarily reported as case studies. The disasters in Minamata, Japan, in the 1950s and in Iraq in 1971-1972 clearly demonstrated neurologic effects associated with ingestion of methylmercury both in adults and in infants exposed in utero. The effects were convincingly associated with methylmercury ingestion, despite limitations of the study design. Several well-conducted studies have investigated the effects of methylmercury at levels below those in the Iraq incident but have not provided clear evidence of an effect. The lower end of the dose-response curve constructed from the Iraq data therefore still needs to be confirmed. The studies of mercury exposure in the workplace were mainly of elemental or inorganic mercury, and effects that were observed at relatively low exposure levels were primarily neurologic and renal. Several studies have investigated effects associated with dental amalgam but have been rated as inconclusive because of methodologic deficiencies. In our overall evaluation, 29 of 110 occupational studies and 20 of 54 studies where exposure occurred in the natural environment provided at least suggestive evidence of an exposure-related effect.

Mercury oxycyanide and mercuric cyanide poisoning: two cases

BACKGROUND

Although cyanide poisoning can be serious or fatal, it is typically described as mild when the cyanide is ingested in the form of either mercuric cyanide or mercury oxycyanide.

METHODS

We studied two patients with acute cyanide poisoning following ingestion of one of these two agents in each case.

RESULTS

Both patients demonstrated features of life-threatening cyanide poisoning, including hemodynamic instability, severe lactic acidosis, and high blood cyanide concentration. One of the patients died, while the second demonstrated signs of mercury intoxication (acute renal failure and severe gastrointestinal symptoms), in addition to cyanide intoxication.

CONCLUSION

Ingestion of either mercuric cyanide or mercury oxycyanide can result in life-threatening cyanide intoxication.

Mercury toxicosis caused by ingestion of a blistering compound in a horse

Mercury toxicosis by ingestion was diagnosed in a 3-year-old Quarter Horse mare with a history of anorexia and signs of abdominal discomfort. Ten and 9 days prior to admission, an inorganic mercuric blistering agent has been applied for topical treatment of dorsal metacarpal disease. At referral, signs of depression, dependent edema, pollakiuria, nonproductive cough, and oral ulceration were noticed. Laboratory data were consistent with renal dysfunction. Mercury content of blood and urine was high, confirming the diagnosis. The horse responded to intensive care, consisting primarily of IV fluid treatment, and mercury-chelating agents. However, acute laminitis developed, and the owners elected to euthanatize the horse 18 days after mercury exposure. Necropsy findings included renal tubulonephrosis and ulcerative colitis and enteritis. Mercury concentration was highest in kidney and liver tissues. The potential for mercury toxicosis in horses currently exists, and although the prognosis is grave, some horses may recover with appropriate treatment and long-term supportive medical care.

[Assessment of early psychic dysfunctions due to metallic mercury]

The aim of the study was to find the most sensitive psychological test battery, useful for evaluation of the earliest dysfunctions in workers exposed to metallic mercury (Hg). To assess the above mentioned disorders, six tests of interference and four tests of motor reactions were applied. The examinations were performed in 44 male workers exposed to Hg in the process of acetic aldehyde synthesis. The control group was matched for sex, age and educational level. The obtained results showed that in the detection od early dysfunctions of the nervous system, psychological tests of interference are more useful than test of the motor reactions. This toxicological test battery can be recommended for monitoring workers exposed to metallic mercury.

Biomarkers in environmental medicine: alterations of cell signalling as early indicators of neurotoxicity

Many environmental and occupational chemicals are known to affect the central and/or peripheral nervous system, causing changes that may result in neurological and psychiatric disorders. Because of the limited accessibility of the mammalian nervous tissue, new strategies are being developed to identify biochemical parameters of neuronal cell function, which can be measured in easily obtained tissues, such as blood cells, as potential markers of the chemically-induced alterations occurring in the nervous system. This review includes a comparative analysis of the effects of mercurials on calcium signalling in the neuroadrenergic PC12 cells and rat splenic T lymphocytes in an attempt to characterize this second messenger system as a potential indicator of subclinical toxicity. The suitability of neurotransmitter receptors in blood cells, such as the sigma binding sites, as biological markers of psychiatric disorders is also discussed.

Mercury kinetics in a case of severe mercuric chloride poisoning treated with dimercapto-1-propane sulphonate (DMPS)

A case of severe mercuric chloride poisoning with clinical signs of mucosal damage of the gastrointestinal tract and anuric renal failure, is presented. The initial whole blood mercury concentration was 14,300 micrograms l-1. This concentration is supposed to be associated with fatal outcome due to multiple organ failure. Because of anuric renal failure, haemodialysis was necessary. Kidney function returned to normal within 10 days. Haemodialysis proved to be ineffective with regard to total mercury elimination. Treatment with DMPS was started because of very severe poisoning, anuric renal failure and optimistic reports on the "new" chelating agent 2,3-dimercapto-1 propanesulphonic acid (DMPS) in mercury poisoning. DMPS was administered by parenteral route initially and was continued thereafter by oral route, until whole blood and urine mercury concentrations had decreased below a level considered as toxic. Except for a temporary pruritic erythema of the skin, no side effects of DMPS treatment were observed. The clinical course was mild, despite continuing high whole blood mercury concentrations. Recovery was uneventful and complete. DMPS treatment, administered by intravenous and oral route, was shown to be an effective alternative for BAL in life-threatening mercuric chloride intoxication. The pharmacokinetic data presented in this case report suggest that non-renal mercury clearance may considerably exceed renal mercury clearance.